Recently I was visiting with one of my professors.
So therefore, it is not our self-esteem that always needs the work, but is instead our self-perceptions, our perception of self.
We can have a strong sense of self-esteem, knowing that we have the tools to withstand adversity and continue on. It is the damage to our self-perception that can effect us on a day to day basis. Something cruel that another person may say to or about us can hurt our feelings and may even alter, temporarily how we perceive ourselves. Yet our self-esteem can still stay intact, with the knowledge that the alteration is only temporary.
Self-confidence, self-esteem, self-importance are all often used interchangeably but they are not the same so I agree with you professor. I believe of these three, self-esteem while up held by our own nature and by ourselves, it is initially developed by others. Because if we are to have self-worth, we need to be able to compare ourselves to other people. We can be important to ourselves with others, we can be confident with out others, but worth by definition needs to have that other option - "opportunity cost" it's called in economics. Thus we need to see and interact with others, and then realize we are all of the same worth, but just bring different aspects/trades to the table.
Hope you are having a good sunday. What class is this by the way?